There are just a few last tweaks that I want to make but the system is essentially complete.

Before:

After:

My sister and I brewed a Belgian IPA using a two step mash. The heat exchanger made easy work of reaching rest temperatures and maintaining them. The mash temperature was maintained by setting the HLT temperature controller 5°F higher than the target mash temperature. The HLT temperature controller activated the HLT burner to maintain its temperature while the mash temperature controller activated the pump to circulate the mash through the heat exchanger. Flow rate was controlled by the manifold valves.

The system worked perfectly for temperature control. However, I have to work on the way the recirculated mash is returned to the mash tun in order to avoid stirring up the grain bed. The return hose had a way of burrowing into the grain bed during recirculation.

Overall, I'm very happy with the results and looking forward to the next batch. Thanks to all of you who followed this topic.